Echocardiography and Ultrasound in Short-Term Mechanical Circulatory Support (MCS)

Overview

  • Talk by Dr. Hatem Soliman on the role of echocardiography (ECHO) and ultrasound in assessing patients on short-term MCS.

  • Covers intra-aortic balloon pump (IABP), Impella, and ECMO.

  • ECHO provides real-time, radiation-free, bedside assessment across all stages of device use.

1️⃣ Intra-Aortic Balloon Pump (IABP)

Mechanism & Role

  • Oldest MCS device (since 1967).

  • Works by counterpulsation—inflates in diastole (↑coronary perfusion) and deflates in systole (↓afterload).

  • Provides ≈ 0.5 L cardiac output support.

Positioning

  • Inserted via femoral artery, balloon lies in descending thoracic aorta.

  • Upper tip = 2 cm below left subclavian artery; lower tip = above renal and mesenteric origins.

  • Transesophageal ECHO (TEE) preferred over fluoroscopy:

    • Confirms positioning and wire location.

    • Detects complications.

    • Rules out aortic dissection, atheroma, or vascular disease.

ECHO Utility

  • Pre-insertion evaluation.

  • Real-time placement guidance.

  • Post-insertion monitoring of LV dimensions, LV function, and LVOT VTI for augmentation efficacy.

2️⃣ Impella Device

Principle & Variants

  • Microaxial flow pump inserted via femoral or subclavian artery.

  • Draws blood from LV → aorta (continuous LV unloading).

  • Impella CP (3.5 L) = percutaneous + pigtail; Impella 5/5.5 L = surgical, no pigtail.

ECHO Guidance

  • Contraindicated in LV thrombus (contrast ECHO distinguishes thrombus from artifact).

  • Positioning: inflow 3.5–4 cm below aortic valve; visible pigtail below teardrop inflow.

  • Malrotation (“Crushed Pigtail Sign”) → suction events, hemolysis, arrhythmia.

  • Requires daily vascular assessment and Doppler for limb ischemia.

3️⃣ Extracorporeal Membrane Oxygenation (ECMO)

Configurations

  • VV ECMO – respiratory support (femoro-jugular or dual-lumen Avalon).

  • VA ECMO – full cardiopulmonary support (peripheral vs central configuration).

ECHO Functions

  • Guides diagnosis, cannulation, contraindication screening, daily monitoring, and weaning.

  • Key signs:

    • LV over-distension → no aortic-valve opening.

    • Differential hypoxia (Harlequin Syndrome): detect via right-hand SpO₂/ABG; managed with reconfiguration (e.g., VV-A).

  • Weaning: stepwise flow reduction (⅓ at a time) with serial ECHO + PAC assessment.

  • RV function crucial for success; assess with Doppler, portal and hepatic-vein flow, and strain imaging.

Key Takeaways

  • ECHO is central to MCS management—from selection to weaning.

  • Assess device position, hemodynamics, and complications continuously.

  • Incorporate multimodal imaging (lungs, hepatic, venous systems).

  • Training and accreditation are essential due to complex MCS–native flow interactions.

 

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